模块化多电平变流器孤网运行控制策略研究

摘要

Modular multilevel converter (MMC) has the advantage of its modular structure allows scattered access to energy storage unit,so it can be used as energy storage converter in microgrid system.Due to a large number of single-phase loads in isolated net system,the output voltage is asymmetry.The control strategy of MMC in two-phase synchronous reference frame is studied.The characteristic of circulating current is analyzed,and the suppression control is designed.Finally,simulation and experimental results verify the validity of the control strategy.%模块化多电平变流器(MMC)以其模块化的结构可使储能单元分散接入的优点,可作为微网系统孤网运行下的储能变流器.由于孤网系统具有大量的单相负荷,会导致输出电压不对称.研究了两相静止坐标系下MMC孤网运行的控制策略,分析了桥臂环流特性,并提出了相应的抑制方法.最后,经过仿真和实验验证了上述控制策略的有效性.